Rodent repellent methods and compositions employing imidazoles



United. States Patent RODENT REPELLENT METHODS AND COMPO- SHTIONS EMPLOYING IMIDAZOLES James-L. Jezl, Swarthmore, and Samuel E. Jolly, Ridley Park, Pa, assignors to Sun Oil Company, Philadelphia, Pa., a corporation of New Jersey No Drawing. Application August 31, 1953 Serial No. 377,673

13 Claims. (Cl. 167-33) This invention relates to the protection of materials from attack by rodents.

The protection of packaged foods and other materials from attack by rodents is a highly important feature of various industries. The cost of goods destroyed or made unusable each year because of gnawing by rodents is presently quite high, and means of combating this destruction are very much in demand. Numerous rodent repellent chemicals have been proposed for the treatment of materials normally subject to attack by rodents. However, the requirements of a satisfactory rodent repellent are diificult to meet. The present invention provides a superior rodent repellency action and protection of materials by the use of certain derivatives of petroleum naphthenic acids.

According to the present invention, materials normally subject to attack by rodents are treated with a 2-naphthenyl imidazole selected from the group consisting of 2-naphthenyl imidazolines and 2-naphthenyl benzimidazoles. It has been found that such compounds are highly effective in preventing rodents from attacking materials which would otherwise be subject to being eaten or gnawed by rodents.

A 2-naphthenyl imidazoline is a compound having a heterocyclic, five-membered ring with nitrogen atoms in the 1 and 3 positions, carbon atoms in the 2, 4, and positions, one double bond only in the heterocyclic ring, which double bond is in the 2,3 position, and a naphthenyl radical, R, derived from petroleum naphthenic acids, RCOOH, attached to the ring in the 2 position.

A Z-naphthenyl benzimidazole is a compound having a heterocyclic, five-membered ring with nitrogen atoms in the l and 3 positions, carbon atoms in the 2, 4, and 5 positions, one double bond only in that portion of the heterocyclic ring exclusive of the aromatic nucleus, which double bond is in the 2, 3 position, the 4 and 5 carbon atoms being also adjacent members of an aromatic nucleus, and a naphthenyl radical, R, derived, from petroleum naphthenic acids, RCOOH, being attached to the heterocyclic ring in the 2 position.

Naphthenyl imidazoles for use according to the present invention can be either substituted or unsubstituted in the 1 position. Thus, there may be either a hydrogen atom connected to the nitrogen atom in the 1 position, or there may be a suitable substituent connected to that nitrogen atom. Suitable substituents for example include aliphatic, haloaliphatic, cycloaliphatic, araliphatic, oxyaliphatic, hydroxyaliphatic, carboxylaliphatic, aminoaliphatic, amidoaliphatic radicals, etc. Such substituents may contain more than one type of functional group, e. g. carboxyl groups as well as amino groups, amido groups as well as amino groups etc. It is preferred that the substituent, if any, in the 1 position should not have more than 25 carbon atoms, and molecular weight not greater than Naphthenyl imidazolines for use according to the present invention can be either substituted or unsubstituted in the 4 position and in the 5 position. If unsubstituted, the

4 carbon atom or the 5 carbon atom has two hydrogen atoms attached thereto. If substituted, the 4 carbon atom or the 5 carbon atom has one or two substituents attached thereto. The types of substituents which may be present are generally similar to those which may be attached to the nitrogen atom in the 1 position. However, preferred 'substituents in the 4 or 5 position are the aliphatic radiand where X is selected from the group consisting of arylene radicals and radicals where r, r, r, and r are each selected from the group consisting of hydrogen and aliphatic radicals, preferably alkyl radicals, having not more than 5 carbon atoms. R may be a straight or branched chain, saturated or unsaturated (containing one or more double bonds) radical; saturated radicals are preferred.

The preparation of Z-naphthenyl imidazoles is known in the art. Generally, it involves reaction of approximately equimolar amounts of petroleum naphthenic acids and a diamino compound or derivative thereof wherein two nitrogen atoms are joined to adjacent carbon atoms. For example, naphthenic acids can be reacted with ethylene diamine to form Z-naphthenyl imidazoline two molecules of water being split out in the reaction. The preparation of Z-naphthenyl imidazolines may be in accordance, for example, with that described in U. S. Patent 2,466,517 to Charles M. Blair and William F. Gross, or with that described in U. S. Patent 2,155,877 to Edmund Waldmann and August Chwala.

Z-naphthenyl benzimidazoles can be prepared by reacting naphthenic acids with phenylene diamine or a derivative thereof, e. g. according to the following reaction:

The reaction can be carried out by refluxing equimolar amounts of the two reactants in a solvent, e. g. xylene, until two moles of water have been split out for each mole of phenylene diamine.

l-substituted-2-naphthenyl imidazoles can be prepared from N-substituted diamines, or by reacting a 2-naphthenyl imidazole with a suitable addition agent, e. g. ethyl bromide, to form the bromide of the 1-ethy1-2-naphthenyl imidazole, and then treating the bromide with a base, e. g. sodium hydroxide to liberate the free 1-ethy1-2- naphthenyl imidazole.

Naphthenyl benzimidazoles for use according to the invention'are'compounds having the formula:

where Ar is an arylene radical and R is a naphthenyl radical. Arylene radicals include monocyclic and polycyclic aromatic residues, which may or may not have substituents thereon, such as alkyl, alkenyl, halogen, or nitro, on one or more of the aromatic rings. Preferably the Ar radical .does not have more than .20 carbon atoms, nor a molecular weight greater than 300.

Any suitable petroleum naphthenic acids can be used to prepare compounds according to the invention. Relatively high molecular weight naphthenic acids, having saponification number for example within the range from 120 to 200 mg. of KOH per gram, are used to advantage, but lower molecular weight acids, having saponification number for example within the range from 200 to 320, can also be used.

The following are examples of compounds for use according the invention: Z-naphthenyl imidazoline, l-methyl-2-naphthenyl imidazoline, l-decyl-Z-naphthenyl imidazoline, l-eicosyl-Z-naphthenyl imidazoline, l-cyclohexylmethyl-Z-naphthenyl imidazoline, l-cyclohexyldecenyl-Z- naphthenyl imidazoline, l-benzyl-Z-naphthenyl imidazoline, l-phenyloctyl-2-naphthenyl imidazoline, l-hydroxymethyl 2 naphthenyl imidazolhie, l-hydroxyhexadecyl 2 naphthenyl imidazoline, l-aminoethyl-2-naphthenyl imidazoline, l-arninohexyl-Z-naphthenyl imidazoline, l-acetamidoethyl-Z-naphthenyl imidazoline, l-beta chloroethyl-Z-naphthenyl imidazoline, l-acetyloxyethyl- Z-naphthenyl imidazoline, l hydroxyhexyl-Z-naphthenyl imidazoline, l-dodecylaminopropyl-Z-naphthenyl imidazoline, l (stearoyloxyethyl) aminoethyl Z-naphthenyl imidazoline, l-(N, N-dodecyl hydroxyethyl) aminoethyl- 2 naphthenyl imidazoline, l stearamidoethyl-Z-naphthenyl imidazoline, l-(N-dodecyl)-acetamidodethylethylaminoethyl 2 naphthenyl imidazoline, l-(hexadecylaminoethyl) aminoethyl-Z-naphthenyl imidazoline, 1- -(hexyloxyethyl) aminopropyl-Z-naphthenyl imidazoline,

l-aniinopropyl-Z-naphthenyl imidazoline, l-triethylenetriamino-Z-naphthenyl imidazoline, l-(N-octyl) diethylenediamino-Z-naphthenyl imidazoline, 1-ethyloxyethyl-2- naphthenyl imidazoline, 1-dodecyloxymethyl-Z-naphthenyl imidazoline, 1-oleyloxyethyl-2-naphthenyl imidazoline, 1-decylaminoethyl-Z-naphthenyl imidazoline, 1- diethylenediamino-Z-naphthenyl imidazoline.

Also constitutingexamples of compounds according to the invention are the benzimidazole compounds corresponding to each of the above imidazoline compounds,

e. g. l-methyl-Z-naphthenyl benzimidazole corresponding i to l-methyl-Z-naphthenyl imidazoline, etc.

Also constituting examples of compounds according to the invention are those compounds corresponding to the benzimidazole compounds referred to in the preceding paragraph but having substituents on the aromatic ring of the benzirnidazole part of the molecule or having a plurality of aromatic rings in that part of the molecule. In such compounds, the radical Ar in the following formula:

maybe, for example, cresyl, dimethylphenyl, ethylphenyl, propylphenyl, triethylphenyl, tetramethylphenyl, vinylphenyl, allylphenyl, chlorophenyl, iodophenyl, bromophenyl, dichlorophenyl, trichlorophenyl, nitrophenyl, dinitrophenyl, chloronitrophenyl, naphthyl, etc.

Also constituting examples of compounds for use ac- 4 cording to the invention are the salts, e. g. hydrohalide, sulfate, oxalate, oleate,-etc. of each of the above imidazolines.

The 2-naphthenyl imidazoles may be employed according to the invention either as the free imidazole or in the form of their salts, either with organic or inorganic acids, e. g. hydrochloric acid, sulfuric acid, acetic acid, oxalic acid, maleic acid, oleic acid, abietic acid, phosphoric acid, petroleum sulfonic acid, napthenic acid, rosin, phenylacetic acid, benzoic acid, picric acid, thiocyanic acid, nicotinic acid, etc.

The Z-naphthenyl imidazoles for use according to the invention include polyimidazoles as ewll as monoimidazoles as previously described. Polyimidazoles can be prepared for example by reaction of a monoimidazole having in the 1 position a substituent containing the grouping NI-ICH CH NH with a carboxylic acid, e. g. naphthenic acid, to form an additional imidazole ring by cyclization of the above grouping. Thus, the following diimidazoline, for example, can be used as a rodent repellent according to the invention:

2-naphthenyl imidazoles for use according to the invention include quaternary salts, which may be formed for example from a l-substituted-Z-naphthenyl imidazole by addition of a suitable compound, e. g. cetyl bromide, to the nitrogen atom in the 1 position to form a quaternary bromide salt.

Various means can be employed for applying Z-naphthenyl imidazoles to materials for protection against rodents. The imidazole can be deposited on an article to be protected by applying an aqueous solution of a water-soluble salt of the imidazole, e. g. a hydrohalide salt. Or the free imidazole can be dispersed in water with the aid of a wetting or dispersing agent and the dispersion applied to the article to be protected. Known types of adhesive or sticking agents can be added to the solution or dispersion to prevent the repellent from being removed by rain or other forms of moisture.

The Z-naphthenyl imidazoles can be incorporated in coating materials such as parafiin or microcrystalline wax, and the wax composition applied to the article to be protected, e. g. a paper package. The imidazoles can be incorporated in plastic coating and film forming materials or in paper pulp, or can be deposited on filers from which bags are to be made, and the imidazole-containing composition can then be made up into packaging means. The imidazoles can also be mixed with suitable dry porous diluents such as clays, talc, and the like and employed as dusts to protect stored goods. The amount of imidazole used as rodent repellent will generally be within the range from 0.01 to 5.0 percent based on the weight of the material to which the imidazole is applied.

The following examples illustrate the invention:

Example 1 2-naphthenyl imidazoline was tested as a rodent repellent in a food acceptance test. The method of test used was essentially the same as that described in an article entitled Rat Deterrents for Paper Packages by Jack F. Welch, James B. De Witt, and Ervin Bellack in the April, May 1950 issue of 'Soap and Sanitary Chemicals. In this test, a repellency index K is determined as described in the article which index indicates the extent to which the rodents used in the test are deterred from eating their normal food by admixing 2% of the test compound, Z-naphthenyl imidazoline in this case, with the food. The highest possible repellency index, K, is 100, which indi cates very good rodent repellency. Low repellency indexes indicate poor rodent repellency or possibly even attraction for rodents. Some compounds are reported by the authors of the above-mentioned journal article to have repellency index as low as -275.

The 2-naphthenyl imidazoline tested was prepared as follows: 125 grams (0.4 mole) of naphthenic acids having saponification number of 179 mg. of KOH per gram were admixed with 24 grams (0.25 mole) of ethylene diamine dihydrate, 40 grams (0.3 mole) of ethylene diamine dihydrochloride, and 100 cc. of xylene. The mixture was heated to reflux temperature and refluxed for about 4 hours until the evolution of water substantially ceased. Xylene was then stripped off, and the temperature of the remaining mixture gradually raised to about 300 C. over a period of about 3 hours in a nitrogen atmosphere. The Z-naphthenyl imidazoline hydrochloride formed was dissolved in water, extracted with naphtha to remove unreacted naphthenic acids, and neutralized with caustic soda to obtain the free Z-naphthenyl imidazoline which weighed 115 grams. This product was distilled to obtain a 086% distillate boiling from 165 C. to 264 C. at 1 mm. of Hg and having refractive index n of 1.5159 and HCl equivalent of 110.7 mg. of HCl per gram, as compared with the theoretical HCl equivalent of 108. The product contained 8.09% nitrogen, as compared with the theoretical nitrogen content of 8.3.

The Z-naphthenyl imidazoline prepared as described above was tested in the manner indicated previously, grams of rat food containing 2% by weight of the imidazoline being placed in a cage with a rat. The imidazolinecontaining food was in one cup and 20 grams of untreated rat food in another cup. Over a four-day period, the respective amounts eaten of treated and untreated food were measured daily, and a repellency index, K, was calculated from the observed data in the manner previously indicated. The following table shows the amounts of untreated and treated food eaten in the indicated periods.

Amount Eaten in Grams (Cumulative) From these data, a repellency index of 85.0 was calculated.

This example shows that Z-naphthenyl imidazolines are superior rodent repellents.

Example 2 2-naphthenyl benzimidazole was tested as a rodent repellent in the same food acceptance test that was used in Example 1. The 2-naphthenyl benzimidazole was prepared as follows: 125 grams (0.4 mole) of naphthenic acids were admixed with grams (0.23 mole) of o-phenylene diamine, 40 grams (0.22 mole) of o-phenylene diamine dihydrochloride, and 100 cc. of xylene. The mixture was heated to reflux temperature and refluxed for about 4 hours until the evolution of water substantially ceased. Xylene was then stripped off, and the temperature of the remaining mixture gradually raised to about 300 C. over a period of about 3 hours in a nitrogen atmosphere. The Z-naphthenyl benzimidazole hydrochloride formed was dissolved in water, extracted with naphtha to remove unreacted naphthenic acids, and neu tralized with caustic soda to obtain the free benzimidazole which weighed 114 grams. This product was a solid glassy material having a nitrogen content of 6.7% (theoretical nitrogen content 7.4%) and a refractive index n of 1.5634. After washing with water, the product had HCl equivalent of 102 mg. of HCl per gram (theoretical HCl equivalent 95).

Amount Eaten in Grams (Cumulative) Time in Days Untreated Food Treated Food PER oeoczo From these data, a repellencey index of 86.5 was calculated.

This example shows that Z-naphthenyl benzimidazoles are superior rodent repellents.

In the preceding examples, naturally occurring petroleum naphthenic acids were used to prepare the derivatives used as rodent repellents. Similar results may be obtained employing, instead of such naturally occurring acids, carboxylic acids obtained by partial oxidation of petroleum hydrocarbon fractions containing substantial quantities, e. g. at least a major proportion of naphthenic hydrocarbons. The term, petroleum naphthenic acids, as used herein, is to be considered as including acids obtained by such partial oxidation as well as naturally occurring acids. Typical oxidation conditions which may be employed in partial oxidation include: temperature 200 F. to 300 F., pressure atmospheric to 500 p. s. i. g., oxidizing agent air, oxygen, ozone, ozonized air, H 0 etc., catalyst, if any, of the well known metal om'dation catalyst, e. g., manganese naphthenate, etc.

The invention claimed is:

1. Method for protecting materials normally subject to attack by rodents which comprises: applying to said materials a rodent repellent composition selected from the group consisting of 2-naphthenyl imidazolines and 2- naphthenyl benzimidazoles and acid salts thereof, said composition being present in a rodent repellent concentration.

2. A material normally subject to attack by rodents, said material having uniformly incorporated therein a rodent repellent composition selected from the group consisting of Z-naphthenyl imidazolines and Z-naphthenyl benzimidazoles and acid salts thereof, said composition being present in a rodent repellent concentration.

3; A packaging material normally subject to attack by rodents impregnated with a rodent repellent composition selected from the group consisting of Z-naphthenyl imidazolines and Z-naphthenyl benzimidazoles and acid salts thereof, said composition being present in a rodent repellent concentration.

4. A material normally subject to attack by rodents, said material having imidazoles uniformly incorporated therein, said imidazoles having the formula:

and having been prepared by converting petroleum naphthenic acids having the formula RCOOH into imidazoles, R being a naphthenyl radical which is attached to a carboxyl group in petroleum naphthenic acids, where'R is selected from the group consisting of hydrogen, alkyl radicals, aminoalkyl radicals and hydroxyalkyl radicals and has molecular weight not substantailly greater than 300; and where X isselected from the group consisting of arylene radicals and .1! ill 7. A paper packaging material normally subject to attack by rodents, said material having been impregnated with wax and with imidazoles having the formula:

prepared by converting petroleum naphthenic acids having the formula RCOOH into said imidazoles, R being a naphthenyl radical which is attached to a carboxyl group in petroleum naphthenic acids, where X is selected from the group consisting of the phenylene radical and the ethylene radical, said imidazoles being present in a rodent repellent concentration.

8. A composition comprising paper having imidazoles uniformly incorporated therein, said imidazoles having the formula:

prepared by converting petroleum naphthenic acids having the formula RCOOH into said imidazoles, R being a naphthenyl radical which is attached to a carboxyl group in petroleum naphthenic acids, Where X is selected from the group consisting of the phenylene radical and the ethylene radical, said imidazoles being present in a rodent repellent concentration. I

10. Method for protection of stored goods which comprises applying to stored goods normally subject to attack by rodents a dusting composition comprising a dry porous diluent and imidazoles having the formula:

prepared by converting petroleum naphthenic acids having the formula RCOOH into said imidazoles, where X is selected from the group consisting of the phenylene radical and the ethylene radical, said imidazoles being present in a rodent repellent concentration.

11. Method according to claim 10 wherein said dry porous diluent is selected from the group consisting of clay and talc.

12. Method according to claim 1 wherein said composition is applied as the sole agent for preventing damage by organisms.

13. Method for protecting materials normally subject to attack by rodents which comprises: applying to said materials an aqueous solution of a rodent repellent composition comprising water-soluble acid salts of compounds selected from the group consisting of Z-naphthenyl imidazolines and Z-naphthenyl benzirnidazoles, said composition being present in a rodent repellent concentration.

References Cited in the file of this patent UNITED STATES PATENTS Blair Apr. 5, 1949 Mitchell Sept. 30, 1952 OTHER REFERENCES 

1. METHOD FOR PROTECTING MATERIALS NORMALLY SUBJECT TO ATTACK BY RODENTS WHICH COMPRISES: APPLYING TO SAID MATERIALS A RODENT REPELLENT COMPOSITION SELECTED FROM THE GROUP CVONSISTING OF 2-NAPHTHENYL IMIDAZOLINES AND 2NAPHTHENYL BENZIMENDAZOLES AND ACID SALTS THEREOF, SAID COMPOSITION BEING PRESENT IN A RODENT REPELLENT CONCENTRATION. 